Pusher used in packaging equipment

ABSTRACT

The present invention aims to provide a pusher used in packaging equipment improved so that undesirable deformation of articles to be packaged can be effectively prevented. 
     A pusher  1  used in the packaging equipment includes ahead unit  36  provided in its frontal end wall  46  with an air supply port  53  and in lateral walls  43  with air suction ports  52.  The air supply port  53  is adapted to maintain fluid-communication between inside and outside of an envelope  2   b  as long as the frontal end wall  46  of the pusher  1  stays inside the envelope  2   b.  The air suction ports  52  are adapted to suck an amount of air inside the envelope  2   b  as the frontal end wall of the pusher  1  moves away from inside of the envelope  2   b  and thereby allow the open end of the envelope  2   b  to be formed with the gussets  57.

REFERENCE TO RELATED APPLICATIONS

This application is a national stage application under 35 USC 371 ofInternational Application No. PCT/JP2008/073037, filed Dec. 18, 2008,which claims the priority of Japanese Applications No. 2008-048441,filed Feb. 28, 2008, and No. 2008-084685, filed Mar. 27, 2008, thecontents of which prior applications are incorporated herein byreference.

FIELD OF THE INVENTION

The present invention relates to pushers used in packaging equipments topush articles to be packaged into individual envelopes through each ofan open end thereof and thereby to obtain packaged articles.

BACKGROUND OF THE INVENTION

In packaging equipments, it is well known to use a pusher by which aplurality of articles to be packaged is into an envelope having a closedend and an open end opposite to the closed end, then to seal the openend and thereby to obtain a finished package. For example, thehigh-speed packaging machine described in JP 61-160002 Y (PATENTDOCUMENT 1) uses a plurality of transverse sealer and a cutter toobtain, from cylindrical plastic film, an envelope having a heat-sealedend and an open end opposite to the heat-sealed end. Using a pusher, anassembly comprising a given number of articles to be packaged is pushedin a lump into this envelope and then the open end is heat-sealed toobtain a finished package. In such packaging machine, it is also wellknown to form both side walls of the pusher with air suction ports,respectively. Specifically, air inside the envelope may be suckedthrough the air suction ports as the pusher moves away from the envelopeafter the pusher has pushed the articles to be packaged into theenvelope. The open end of the envelope is formed with gussets as thepusher moves away from the envelope and finally the open end isheat-sealed.

SUMMARY OF THE INVENTION

According to the pusher of prior art as has been exemplarily describedabove, the inside of the envelope is apt to be in a depressurizedcondition as the pusher moves away from the envelope. Particularly whenthe articles constituting the assembly to be packaged are of flexiblenature and the envelope also is made of flexible material such asplastic film or paper, undesirable deformation of the envelope under thedepressurized condition may cause the assembly of the articles to beundesirably deformed. As consequence, expected function of theindividual articles may be deteriorated when these articles are actuallyused and, in addition, the appearance thereof also may be disfigured.Furthermore, the outer shapes of these individual articles may becomeuneven and make it difficult to stack the articles in an orderlyfashion, for example, in the shop.

In the case of the prior art exemplarily described above, the pusher'sforehead is preferably dimensioned to have the area as large as possibleso that the forehead of the pusher may push the assembly of the articlesover an area as large as possible. In fact, such measure is advantageousin that uniform suppress strength may be exerted on the assembly of thearticles over an area as large as possible and damage of the individualarticles due to use the pusher may be restricted. However, the largerthe area of the pusher' forehead is, the more tightly the inner surfaceof the envelope comes in close contact with the pusher and, inconsequence, it may become difficult for the envelope to be deformedneatly along the grooves of the pusher. As a result, it may becomedifficult to form instantly the envelope with neat gussets.

In view of the various problems as have been described above, it is aprincipal object of the present invention to improve the pusher used inthe packaging equipment so that these problems involved with theassembly of the articles to be packaged as well as with the finishedpackage may be effectively eliminated.

The present invention to achieve the object set forth above includes afirst aspect and a second aspect. The object set forth above isachieved, according to the first aspect of the present invention, by animprovement in the pusher used in packaging equipment, the pusheroperating to push articles to be packaged into an envelope having aclosed end and an open end opposite to the closed end, then to seal theopen end concurrently with formation of gussets on both sides of theopen end and thereby to obtain a finished package comprising theenvelope and the articles to be packaged.

The improvement according to the first aspect of the present inventionis characterized in that: the pusher is adapted for to-and-fro movementin a forward direction in which the articles to be packaged are pushedinto the envelope and in a rearward direction opposed to the forwarddirection and includes a head unit having a frontal end wall adapted tobe pressed against the articles to be packaged and to move into theenvelope, a rear end wall opposed to the frontal end wall and bothlateral walls defined between the frontal end wall and the rear end walland extending in parallel to each other in the forward direction; thefrontal end wall is provided with an air supply port adapted to maintaina fluid-communication between inside and outside of the envelope by anintermediary of the pusher so long as the frontal end wall lies insidethe envelope; and the lateral walls are respectively provided with airsuction ports allowing the open end of the envelope to be formed withthe gussets as the frontal end wall moves away from the inside of theenvelope in the opposite direction.

According to one preferred embodiment of the present invention on thefirst aspect thereof, the air supply port provided in the frontal endwall of the head unit is kept in fluid-communication with ambient airbetween the frontal end wall and the rear end wall, on the rear end wallor behind the rear end wall.

According to another preferred embodiment of the present invention onthe first aspect thereof, the air supply port provided in the frontalend wall of the head unit is adapted to supply an inside of the envelopewith pressurized air.

According to still another preferred embodiment of the present inventionon the first aspect thereof, the lateral walls are respectively formedwith V-shaped grooves extending from the frontal end wall toward therear end wall and the V-shaped grooves are formed in respective surfacesthereof with the air suction ports.

The object set forth above is achieved, according to the second aspectof the present invention, by an improvement in the pusher used inpackaging equipment, the pusher operating to push a plurality ofarticles to be packaged into an envelope having a closed end and an openend opposite to the closed end, then to seal the open end concurrentlywith formation of gussets on both sides of the open end and thereby toobtain a finished package comprising the envelope and the articles to bepackaged.

The improvement according to the second aspect of the present inventionis characterized in that: said pusher being characterized in that: thepusher is adapted for to-and-fro movement in a forward direction inwhich the articles to be packaged are pushed into the envelope and in arearward direction opposed to the forward direction and includes a headunit having a frontal end wall adapted to be pressed against thearticles to be packaged and to move into the envelope, a width directionextending orthogonally to the direction of the to-and-fro movement and athickness direction extending orthogonally to both the direction of theto-and-fro movement and the width direction; the head unit is divided intwo, i.e., a first plate and a second plate face each other in thethickness direction or divided in three, i.e., a first plate, a secondplate and a third plate, the first plate being interposed between thesecond plate and the third plate wherein both sides of the first platein the width direction are respectively formed with V-shaped groovesextending in the direction of the to-and-fro movement and utilized toform the gussets and the grooves are formed with ports connected to avacuum suction source; the head unit operates in a manner such that, ina course of movement in the forward direction of the pusher, the secondplate and the third plate cooperate with the first plate to push thearticles to be packaged into the envelope and, in a course of movementin the rearward direction of the pusher occurring after the articles tobe packaged have been fully pushed into the envelope, the second plateand the third plate move away from the envelope leaving the first platetherein, and thereafter the first plate moves away from the envelope tosubject the envelope to vacuum from the vacuum suction source; and afrontal end sub-wall defined by any one of the first, second and thirdplates has an air supply port adapted to maintain fluid-communicationbetween inside and outside of the envelope as long as the frontal endwall lies inside the envelope.

According to one preferred embodiment of the present invention on thesecond aspect thereof, the second plate and the third plate areintegrated with each other behind the head unit.

According to another preferred embodiment of the present invention onthe second aspect thereof, the air supply ports are adapted to supply aninside of the envelope with pressurized air.

The pusher according to the first aspect of the present invention hasthe air supply port provided in the frontal end wall of the head unitand the air suction ports provided in the both lateral walls. With sucharrangement, there is practically no possibility that the central regionof the envelope containing the articles to be packaged having pushedthereinto might be trapped in the depressurized condition even when airinside the envelope is sucked through the air suction ports in order toform the open end of the envelope with the gussets as the head unitmoves away from the envelope after the articles to be packaged have beenpushed into the envelope. In this way, undesirable deformation of thearticles to be packaged due to formation of the gussets can bepractically prevented.

The pusher according to the second aspect of the present inventionincludes the head unit comprising the first plate and the second plateoverlapping each other in the height direction or comprising the firstplate, the second plate and the third plate wherein the first plateinterposed between the second and third plates so that only the secondplate or the second plate and the third plate may move away from theenvelope after the articles to be packaged have been pushed into theenvelope and only the first plate may be used to form the gussets. Withsuch unique arrangement, even if the envelope has been put in closecontact with the head unit in the course of pushing the articles to bepackaged into the envelope, the envelope is not in close contact withthe head unit in the course of forming the gussets. Consequentially,even if the grooves of the first plate utilized to form the gussets arerelatively deep, the envelope can quickly and smoothly move into thegrooves to be deformed in accordance with the shape of the respectivegrooves. In this way, the neat gussets can be quickly obtained.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of an envelope and articles to be packaged.

FIG. 2 is a side view of packaging equipment using a pusher.

FIG. 3 is a detailed diagram illustrating a process of packaging byfollowing steps 3A through 3E.

FIG. 4 is a sectional view taken along the line IV-IV in FIG. 3.

FIG. 5 is a diagram exemplarily illustrating a manner in which thepusher is used.

FIG. 6 is a perspective view of the envelope and the articles to bepackaged.

FIG. 7 is a side view of the packaging equipment using the pusher.

FIG. 8 is a perspective view of the pusher.

FIG. 9 is a sectional view taken along the line IX-IX in FIG. 8.

FIG. 10 is a detailed diagram illustrating a process of packaging byfollowing steps (a) through (f).

FIG. 11 is a diagram exemplarily illustrating a manner in which thepusher is used.

FIG. 12 is a view similar to FIG. 9, showing the head member accordingto another embodiment.

FIG. 13 is a perspective view of the finished package obtained by usingthe head member shown by FIG. 12.

IDENTIFICATION OF REFERENCE NUMERALS USED IN THE DRAWINGS

1 pusher

2, 2 a, 2 b envelope

4 closed end

5 open end

10 packaging equipment

14 finished package

15, 15 a assembly of individually packaged articles

36 head unit

41 front end wall

42 rear end wall

43 lateral walls

51 V-shaped grooves

52 air suction ports

53 air supply port

57 gussets

101 pusher

110 packaging equipment

136 head unit

141 frontal end wall

151 first plate (main plate)

152 second plate (upper sub-plate)

153 third plate (lower sub-plate)

156 grooves

157 ports (suction ports)

158 air supply ports

A to-and-fro movement direction (machine direction)

B width direction (cross direction)

T height direction

DETAILED DESCRIPTION OF THE INVENTION

Details of the pusher according to the present invention adapted to beused in the packaging equipment will be more fully understood from thedescription of preferred embodiments given hereunder with reference tothe accompanying drawings.

FIG. 1 shows an envelope 2 for which a pusher 1 (See FIGS. 2 and 3)according to the present invention is used and articles to be packagedin the envelope 2, more specifically, an assembly 15 comprising aplurality of individual menstruation napkin-packages 3. The envelope 2is made of, for example, a flexible and air-impervious plastic film andhas a closed end 4 formed with heat-seal 2 d and an open end 5 oppositeto the closed end 4. Between the closed end 4 and the open end 5, a pairof lateral walls 7 formed with a pair of gussets 6, respectively. Eachof the individual napkin-packages 3 comprises a menstruation napkin (notshown) and a bag 3 a made of flexible sheet material such as a plasticfilm or a nonwoven fabric wherein a given number of such individualnapkin-packages which will be packaged in the envelope 2 are orderlyarranged in a machine direction A (See FIG. 2 also) and in a crossdirection B extending orthogonally to the machine direction A to formthe assembly 15.

FIG. 2 is a lateral diagram schematically illustrating packagingequipment 10 using the pusher 1 according to the present invention.Operation of the packaging equipment comprises a first feeding step 11in which the envelopes 2 are intermittently fed, a second feeding step12 in which the assembly 15 of the individual napkin-packages 3 isintermittently fed and a packing step 13 in which the finished packages14 (See FIG. 3 also) are successively obtained.

In the first feeding step 11 illustrated in FIG. 2, the envelopes 2 eachpreviously formed with the gussets 6 associated with the closed end 4are intermittently fed with the open end 5 ahead from the left hand asviewed in FIG. 2. Top and bottom surfaces 8, 9 (See FIG. 1) of theenvelope 2 are respectively sucked by upper and lower suction plates 16for flaring and thereby the open end 5 is flared as shown by FIG. 1. Thesuction plates 16 horizontally move in a direction of the arrow C to putthe flared open end 5 on one bucket 21 a of a plurality of buckets 21and then move away from the open end 5 to respective initial positionsas illustrated in FIG. 2. The buckets 21 serve to maintain the open end5 in the flared state and, in FIG. 2, the envelope 2 put on the onebucket 21 a of the buckets 21 is indicated as the envelope 2 a contouredby the imaginary line. These buckets 21 are mounted on a disc 22 adaptedto be intermittently clockwise or counterclockwise rotated so that theenvelope 2 a put on the bucket 21 a is rotated integrally rotated by180° and thereby moved from the upper-side to the lower-side as viewedin FIG. 2. In FIG. 2, the envelope 2 a having moved downward isindicated as the envelope 2 b contoured by the imaginary line and thebucket 21 a is indicated as the bucket 21 b.

In the second feeding step 12 illustrated in FIG. 2, the assembly 15 istransported on a conveyor 17 in a direction of the arrow D andtransferred to a lifter 18 included in the conveyor 17. The lifter 18 isvertically movable to transfer the assembly 15 loaded on the conveyor 17upward as indicated by the arrow E. In FIG. 2, the assembly 15 havingbeen moved in this manner is indicated as the assembly 15 a. In theconveyor 17, an endless belt 17 a adapted to be intermittently moved isprovided with a plurality of pins 17 b at regular intervals so that theassembly 15 slidably loaded on a support means (not shown) on theconveyor 17 is pushed by the pin 17 b from the right as viewed in FIG.2, i.e., in the direction of the arrow D and thereby moved in thedirection of the arrow D.

The packing step 13 in FIG. 2 involves the pusher 1, upper and lowerpressure plates 31, upper and lower seal plates 32 and an endless belt33. The pusher 1 includes a head unit 36 at the left hand as viewed inthe machine direction A and a rod unit 37 at the right hand as viewed inthe machine direction A, respectively. The rod unit 37 is interlockedwith a drive mechanism (not shown) causing to-and-fro movement of thepusher 1 in the machine direction A and, in FIG. 2, the pusher 1 isshown to be in its retracted position. In the packing step 13, theenvelope 2 b, the bucket 21 b on which the envelope 2 b is put, theassembly 15 a having moved upward and the pusher 1 are aligned' in themachine direction A. The pusher 1 is moved leftward so that the headunit 36 thereof may come in contact with and push the assembly 15 a intothe bucket 21 b. The head unit 36 is moved further forward to push theassembly 15 a into the envelope 2 b and then to push the envelope 2 bleftward by the intermediary of the assembly 15 a until the envelope 2 bcontaining therein the assembly 15 a comes free from the bucket 21 b andis loaded on the endless belt 33. Then, the head unit 36 moves away fromthe envelope 2 b rightward in the machine direction A and simultaneouslythe two pressure plates 31 move in a vertical direction so as to getclose to each other and thereby to prevent the envelope 2 b from movingrightward. In response to the head unit 36 moving away from the envelope2 b, the two heated seal plates 32 move in a vertical direction so as toget close to each other until these heated seal plates 32 pinch the openend 5 of the envelope 2 b and thereby form a heat-seal 2 e (See FIG. 3).The seal plates 32 move back to the respective positions as illustratedand a finished package 14 is obtained. The finished package 14 istransported leftward by the endless belt 33.

FIG. 3 is a diagram illustrates details of the packing step 13 whereinthe lifter 18 and the disc 22 are not illustrated for simplicity. In aphase illustrated by FIG. 3A, the bucket 21 b having the envelope 2 bput thereon, the assembly 15 a and the pusher 1 are aligned in themachine direction A. The head unit 36 of the pusher 1 has a front endportion 41 and a rear end portion 42 opposite to the front end portion41 between which a pair of lateral walls 43 and top and bottom walls 44,45 are defined. The front end portion 41 includes a front surface 46(See FIG. 4) adapted to come in contact with the assembly 15 and therear end portion 42 includes a rear surface 47 adapted to be connectedwith the rod unit 37. The lateral walls 43 are formed with V-shapedgrooves 51 extending from the front end portion 41 toward the rear endportion 42 and surfaces of the respective V-shaped grooves 51 are formedwith air suction ports 52. The air suction ports 52 arefluid-communication with air suction means such as a vacuum pump so thatair inside the envelope 2 b may be sucked through these air suctionports for a predetermined time period in the packing step 13. The frontsurface 46 is formed with an air supply port 53 (See FIG. 4). The airsupply port 53 is fluid-communication with ambient air via a ductwork(not shown) extending within the head unit 36 or connected to acompressed air supply source (not shown) such as a compressor. Theductwork provided in the case of the air supply port 53 adapted to be influid-communication with ambient air will have its open end in a regionbetween the front end portion 41 and the rear end portion 42, in therear end portion 42 or a region behind the rear end portion 42.

In a phase illustrated by FIG. 3B, the head unit 36 moves forward topush the assembly 15 a into the tunnel-like bucket 21 b and furthermoves forward to push the assembly 15 a into the envelope 2 b until theenvelope 2 b comes free together with the assembly 15 a from the bucket21 b.

In a phase illustrated by FIG. 3C, the head unit 36 begins to move awayfrom the envelope 2 b and simultaneously a pair of the pressure plates31 begins to get close to each other. In the head unit 36, in turn, theair suction port 52 starts to be activated and, in response thereto, thelateral walls 7 of the envelope 2 b begins to be deformed in accordancewith the V-shape of the respective grooves 51 in the vicinity of theopen end 5 and the gussets 57 (See FIG. 3E) begin to be formed. When thefront end portion 41 lies inside the envelope 2 b, the air supply port53 of the head unit 36 is maintained in fluid-communication with theambient air or the inside of the envelope 2 b can be supplied withcompressed air as the head unit 36 moves away from the envelope 2 b and,in each case, fluid-communication is maintained between the inside andthe outside of the envelope 2 b. As a consequence, it is possible toprevent a central region of the envelope 2 b from being rearwardmovement of the head unit 36 or vacuum suction might unacceptablydepressurize a central region of the envelope 2 b containing therein theassembly 15. If the menstruation napkin contained in the individualpackage 3 has a sufficient elastic recovery, the assembly 15 iscompressed and its volume is decreased as the pusher 1 moves forward topush the assembly 15 and decompressed and its volume is increased againas the pusher 1 moves rearward. The envelope 2 b would otherwise betrapped in so-called depressurized condition as the pusher 1 movesrearward. However, the pusher 1 may be provided with the air supply port53 to present the envelope 2 b from being trapped in such depressurizedcondition.

In a phase of FIG. 3D, the heated upper and lower seal plates 32 getclose to each other about the envelope 2 b from which the head unit 36has moved away and pinch the open end 5 of the envelope 2 b to form theheat-seal 2 e (See FIG. 3E).

FIG. 3E illustrates the finished package 14 obtained in the packing step13. The finished package 14 is formed with, in addition to thepreviously formed heat-seal 2 d, the heat-seal 2 e. In the finishedpackage 14, the lateral walls 7 of the envelope 2 are formed with thegussets 56, 57, respectively, in the vicinity of the heat-seals 2 d, 2e.

FIG. 4 is a sectional view taken along the line IV-IV in the head unit36 illustrated by FIG. 3A. In FIG. 4, a part of the front surface 46 ofthe head unit 36 constituting the pusher 1 and one of the V-shapedgrooves 51 of the lateral walls 43. The front surface 46 is formed withthe air supply port 53. V-shaped groove 51 is laterally facing andprovided in its surface with the air suction port 52. The envelope 2 bindicated by the imaginary line along the V-shaped groove 51 is deformedunder vacuum exerted through the air suction port 52 and starts to formthe gusset 57. It should be noted here that, in the case of the pusher 1according to the present invention, the central region of the envelope 2is assured to be maintained in fluid-communication with ambient air orsupplied with compressed air via the air supply port 53 formed in thehead unit 36 even the vacuum suction to form the envelope 2 with thegussets 57 begins. Consequentially, the envelope 2 would not be trappedin the depressurized condition. In this way, the individual packages 3constituting the assembly 15 would not be compressed by depressurizedenvelope and thereby deformed. In addition, the finished package wouldnot be undesirably deformed and therefore it is facilitated to stack aplurality of the finished packages 14 for bale packaging or displaying.In the pusher 1, timing control for starting and ending of air suctionthrough the air suction port 52 and for starting and ending of airsupply through the air supply port 53 can be done by providing thepackaging equipment with control mechanisms (not shown) operativelyassociated with these timing control operations. In the pusher 1, theV-shaped grooves 51 in the illustrated embodiment may be replaced byU-shaped grooves or the other various types of grooves.

FIG. 5 is a diagram similar to FIG. 3A exemplarily illustrating a mannerin which the pusher 1 is used. Referring to FIG. 5, the envelope 2 b hasbeen put on the bucket 21 b and the closed end 4 has moved into thebucket 21 b from the left hand and in the machine direction A. Theclosed end 4 has its inner surface exposed and faces the assembly 15 a.The assembly 15 a comes in contact with the inner surface of the closedend 4 of the envelope 2 b as the assembly 15 a is pushed by the pusher 1into the bucket 21 b. The assembly 15 a is moved into the envelope 2 buntil the position shown by FIG. 3B is reached as the pusher 1 is movedforward. To bring the envelope 2 b into the state of FIG. 5, after theopen end 5 has been put on the bucket 21 b, pressurize air may beinjected from outside of the closed end 4 into the envelope 2 b andthereby the closed end 4 may be forced to move into the bucket 21 b fromthe left hand as viewed in FIG. 5.

According to the embodiment illustrated by FIG. 5, when the pusher 1 isused to push the assembly 15 a into the envelope 2 b, air would not beconfined within the envelope 2 b in front of the assembly 15 a.Consequentially, the compact finished package 14 can be obtained.

While the pusher 1 and packaging equipment 10 including this pusher 1having been described hereinabove with reference to FIGS. 1 through 5are suitable for packaging of the flexible and easily deformablearticles such as menstruation napkins and disposable diapers, it isobvious that these pusher 1 and packaging equipment 10 can beeffectively used for the other articles which are not easily deformable.

FIG. 6 shows an envelope 2 for which a pusher 101 (See FIGS. 7 and 8)according to one preferred embodiment of the present invention is usedand articles to be packaged in the envelope 2, more specifically, anassembly 15 comprising a plurality of individual menstruationnapkin-packages 3. The envelope 2 is made of, for example, flexible andair-impervious plastic film and has a closed end 4 formed with heat-seal2 d and an open end 5 opposite to the closed end 4. Between the closedend 4 and the open end 5, a pair of lateral walls 7 formed with a pairof gussets 6, respectively. Each of the individual menstruationnapkin-packages 3 comprises a menstruation napkin (not shown) and a bag3 a made of a flexible sheet material such as a plastic film or anonwoven fabric wherein a given number of such individual menstruationnapkin-packages which will be packaged in the envelope 2 are orderlyarranged in a machine direction A (See FIG. 7 also) and in a crossdirection B extending orthogonally to the machine direction A to formthe assembly 15.

FIG. 7 is a lateral diagram schematically illustrating packagingequipment 110 using the pusher 101 according to the present invention.Operation of the packaging equipment 110 comprises a first feeding step11 in which the envelopes 2 are intermittently fed, a second feedingstep 12 in which the assembly 15 of the individually packaged articles 3is intermittently fed and a packing step 13 in which the finishedpackages 14 (See FIG. 6 also) are successively obtained.

In the first feeding step 11 illustrated in FIG. 7, the envelopes 2 eachpreviously formed with the gussets 6 associated with the closed end 4are intermittently fed with the open end 5 ahead from the left hand asviewed in FIG. 7. Top and bottom surfaces 8, 9 (See FIG. 6) of theenvelope 2 are respectively sucked by upper and lower suction plates 16for flaring and thereby the open end 5 is flared as shown by FIG. 6. Thesuction plates 16 horizontally move in a direction of the arrow C to putthe flared open end 5 on one bucket 21 a of a plurality of buckets 21and then move away from the open end 5 to respective initial positionsas illustrated in FIG. 7. The buckets 5 serve to maintain the open end 5in the flared state and, in FIG. 7, the envelope 2 put on the one bucket21 a of the buckets 21 is indicated as the envelope 2 a contoured by theimaginary line. These buckets 21 are mounted on a disc 22 adapted to beintermittently clockwise or counterclockwise rotated so that theenvelope 2 a put on the bucket 21 a is rotated integrally rotated by180° and thereby moved from the upper-side to lower-side as viewed inFIG. 7. In FIG. 7, the envelope 2 a having moved downward is indicatedas the envelope 2 b contoured by the imaginary line and the bucket 21 ais indicated as the bucket 21 b.

In the second feeding step 12 illustrated in FIG. 7, the assembly 15 istransported on a conveyor 17 in a direction of an arrow D andtransferred to a lifter 18 included in the conveyor 17. The lifter 18 isvertically movable to transfer the assembly 15 loaded on the conveyor 17upward as indicated by the arrow E. In FIG. 7, the assembly 15 havingbeen moved in this manner is indicated as the assembly 15 a. In theconveyor 17, an endless belt 17 a adapted to be intermittently moved isprovided with a plurality of pins 17 b at regular intervals so that theassembly 15 slidably loaded on a support means (not shown) on theconveyor 17 is pushed by the pin 17 b from the right hand as viewed inFIG. 7, i.e., in the direction of the arrow D and thereby moved towardthe lifter 18.

The packing step 13 in FIG. 7 involves the pusher 101, upper and lowerpressure plates 31, upper and lower seal plates 32 and an endless belt33. The pusher 101 includes a head unit 136 at the left hand as viewedin the machine direction A and a rod unit 137 at the right hand asviewed in the machine direction A, respectively. The rod unit 137 isinterlocked with a drive mechanism (not shown) causing to-and-fromovement the pusher 101 in the machine direction A and, in FIG. 7, thepusher 101 is shown to be in its retracted position. In the packing step13, the envelope 2 b, the bucket 21 b on which the envelope 2 b is put,the assembly 15 a having moved upward and the pusher 101 are aligned inthe machine direction A. The pusher 101 is moved leftward as viewed inthe machine direction A so that the head unit 136 thereof may come incontact with and push the assembly 15 a into the bucket 21 b. The headunit 136 moves further forward to push the assembly 15 a into theenvelope 2 b and then to push the envelope 2 b leftward by theintermediary of the assembly 15 a until the envelope 2 b containingtherein the assembly 15 a comes free from the bucket 21 b and is loadedon the endless belt 33. A part of the head unit 136 having completed itsfunction to push the assembly 15 a into the envelope 2 b remains insidethe envelope 2 b together with the assembly 15 a. Then, the head unit136 moves away from the envelope 2 b rightward in the machine directionA and simultaneously the two pressure plates 31 move in a verticaldirection so as to get close to each other and thereby to prevent theenvelope 2 b from moving rightward. In response to the head unit 36fully moving away from the envelope 2 b, the two heated seal plates 32move in a vertical direction so as to get close to each other untilthese heated seal plates 32 pinch the open end 5 of the envelope 2 b andthereby form a heat-seal 2 e (See FIG. 8). The seal plates 32 move backto the respective positions as illustrated and a finished package 14 isobtained. The finished package 14 is transported leftward by the endlessbelt 33.

FIG. 8 is a perspective view of the pusher 101 and FIG. 9 is a sectionalview taken along the line IX-IX in FIG. 8. In FIG. 9, the envelope 2 binto which the pusher 101 has moved and the envelope 2 b′ beginning tobe formed with the gusset 61 (See FIG. 10) as an upper sub-plate 152 anda lower sub-plate 153 are moved away from the envelope 2 b are indicatedby the imaginary lines. Referring to FIG. 8, the head unit 136 of thepusher 101 has a horizontal to-and-fro movement direction correspondingto the machine direction A, a width direction corresponding to the crossdirection B orthogonal to the machine direction A and a height directionT orthogonal to both the to-and-fro movement direction and the widthdirection. As viewed in the height direction T, the head unit 136comprises three plates, i.e., a main plate 151 as a first plate, andupper and lower sub-plates 152, 153 as second and third plates,respectively, arranged to sandwich the main plate 151 therebetween. Themain plate 151, the upper sub-plate 152 and the lower sub-plate 153 areadapted for to-and-fro movement in the machine direction A which isindependent one from another. Specifically, a main rod 137 functioningto actuate to-and-fro movement of the main plate 151 is attached to arear end wall 151 b of the main plate 151, a sub-rod 138 functioning toactuate to-and-fro motion of the upper sub-plate 152 is attached to aside plate 152 b of the upper sub-plate 152 and a sub-rod 139functioning to actuate to-and-fro movement of the lower sub-plate 153 isattached to a side plate 153 b of the lower sub-plate 153. The main rod137 and the sub-rods 138, 139 are respectively connected to drivesources (not shown) such as pistons.

The main plate 151, the sub-plate 152 and the sub-plate 153 respectivelyhave a main frontal end wall 151 a, a frontal end sub-wall 152 a and afrontal end sub-wall 153 a integrated together to define a frontal endwall 141 of the pusher 101. These main front end wall 151 a, the frontend sub-wall 152 a and the frontal end sub-wall 153 a are regionscooperating together to be pressed against the assembly 15 as the pusher101 moves forward. To prevent the contact pressure from being locallyexerted on the assembly 15, the frontal end wall 141 of the pusher 101integrally defined by the frontal surface wall 151 a, 152 a and 153 amay be shaped and sized to be generally coincident with those of aregion 19 of the assembly 15 facing the frontal end wall 141 of thepusher 101 or to be slightly smaller than the size of this region 19 ofthe assembly 15. In other words, the maximum dimension of the frontalend wall 141 as measured in the cross direction B and the heightdirection T may be set to be generally the same as or slightly smallerthan the maximum dimension of the region 19 of the assembly 15.

The pusher 101 further includes a pair of lateral walls 142symmetrically shaped as viewed in the cross direction B. Each of thelateral walls 142 comprises a main lateral wall 151 c in the main plate151, a lateral sub-wall 152 c of the sub-plate 152 and a lateralsub-wall 153 c of the sub-plate 153 wherein the main lateral wall 151 cis formed with a groove 15 extending from the frontal wall 151 a in themachine direction A and having a V-shaped cross-section and the groove151 c is formed with a suction port 157. The suction port 157 isconnected to an air suction source (not shown) such as a vacuum pump.The lateral sub-walls 152 c, 153 c are smoothly finished. Referring toFIG. 9, the main frontal end wall 151 a of the frontal end wall 141 isformed with an air supply port 158. The air supply port 158 extends toan air inlet 159 formed in a main rear end wall 151 b of the main plate151 and fluid-communicates with ambient air.

FIG. 10 is a diagram illustrates details of the packing step 13 whereinthe lifter 18 and the disc 22 are not illustrated for simplicity. In aphase of FIG. 10A, the bucket 21 b having the envelope 2 b put thereon,the assembly 15 a and the pusher 101 are aligned in the machinedirection A wherein the region 19 of the assembly 15 a faces the frontalend wall 41 of the pusher 101.

In a phase of FIG. 10B, the head unit 136 moves forward and is pressedagainst a generally entire area of the region 19 of the assembly 15 a topush the assembly 15 a into the tunnel-like bucket 21 b and then intothe envelope 2 b until the envelope 2 b comes free from the bucket 21 b.A part of the head unit 136 moves into the envelope 2 b.

In a phase of FIG. 10C, with the main plate 151 remaining at rest, theupper sub-plate 152 and the lower sub-plate 153 are moved away from theopen end 5 of the envelope by the sub-rod 138 and the sub-rod 139,respectively. A pair of the pressure plates 31 moves closer to theenvelope 31 and thereby prevents the envelope 2 b from moving as theupper and lower sub-plates 152, 153 begin to move back.

In a phase of FIG. 10D, the main plate 151 which has remained stationaryin the phase of FIG. 10C begins to move away from the envelope 2 b and apair of the pressure plates 31 moves further closer to the envelope 2 b.In the main plate 151, air inside the envelope 2 b begins to be suckedvia the suction port 157 and, in consequence, the lateral walls 7 of theenvelope 2 b begin to be deformed in the vicinity of the open end 5 inaccordance with the shape of the respective grooves 156. In this way,the gussets 61 (See FIG. 10F) begin to be formed. Even when the frontalend wall 151 a of the main plate 151 is still lies inside the envelope 2b, the air supply ports 158 (See FIG. 9) are in fluid-communication withambient air and thereby ventilation is assured between inside andoutside of the envelope 2 b. Consequentially, backward movement of themain plate 151 and the sub-plates 152, 153 and/or air suction by thesuction port 157 of the main plates 151 would not bring the centralregion of the bag 2 b into depressurized state. Thereby it is possibleto prevent the assembly 15 having been pushed into the central region ofthe envelop 2 b from being undesirably deformed due to the air suctioneffect. In the case of the individual menstruation napkin-packageshaving elastic recovery property, certainly there is a possibility thatthe assembly 15 might have its volume decreased as the assembly 15 ispushed by the pusher 101 moving forward and might have its volumeincreased and might be brought into depressurized state as the pusher101 moves backward. However, the air supply port 158 of the pusher 101can reliably prevent the assembly 15 from becoming such depressurizedstate.

In a phase of FIG. 10E, a pair of heated seal plate 32 moves closer toeach other about the envelope 2 b from which the main plate has movedaway and forms the open end 5 of the envelope 2 b with the heat-seal 2 e(See FIG. 10F). While not illustrated, the main plate 151, the uppersub-plate 152 and the lower sub-plate 153 having moved back areposition-adjusted so that the frontal end wall 151 a, 152 a and 153 aare positioned as illustrated by FIG. 8.

FIG. 10F illustrates the finished package 14 having been obtained in thepacking step 13. The finished package 14 has, in addition to thepreviously formed heat-seal 2 d as seen in FIG. 6, the heat-seal 2 ewhich has been formed on an end wall 62 of the finished package 14substantially at a middle level as viewed in a vertical direction ofFIG. 10F. In the vicinity of the heat-seals 2 d, 2 e, respectively, thelateral walls 7 of the envelope 2 in the finished package 14 have beenformed with the gussets 6, 61, respectively.

The process in which the gussets 61 are formed in the vicinity of theopen end 5 in the step of FIG. 10D is illustrated also by FIG. 9.Specifically, the main plate 151 constituting the head unit 136 isformed in the V-shaped groove 156 thereof with the suction ports 157 andthe envelope 2 b indicated by the imaginary line is formed with thegussets 61 under vacuum acting upon the envelope 2 b via the suctionport 157. However, it should be noted here that, in the step of FIG.10D, the gussets 61 are formed after the upper and lower sub-plates 152,153 have moved away from the envelope 2 b. Immediately before vacuumacts upon the envelope 2 b along the grooves 156 to deform the envelope2 b in accordance with the shape of the respective grooves 156, portionsof the envelope 2 b having been in a state of tension due to closecontact with the upper and lower sub-plates 152, 153 are relaxed as theupper and lower sub-plates 152, 153 move away from the envelope 2 b sothat the envelope 2 b may be easily deformed in accordance with theshape of the respective grooves 156. In this way, it is easily possiblefor the pusher 101 to form the envelope 2 b with the gussets 61 even ifthe envelope 2 b has partially been in close contact with the head unit136 when the pusher 101 has pushed the assembly 15 into the envelope 2b.

The unique arrangement of the head unit 136 as has been described aboveeffectively facilitates the operation of deforming the envelope 2 balong the grooves 156 as indicated by the imaginary lines and therebyforming the gussets 61 without damaging the assembly 15 a. A beneficialeffect can be expected from such head unit 136 when an open angle alphaof the groove 156 is set to be as small as possible and thereby a depthin the cross section B of the gusset 61 formed by the main plate 151 isset to be as large as possible.

In the case of the pusher 101 according to the present invention, thecentral region of the envelope 2 is assured to be maintained influid-communication with ambient air or supplied with compressed air viathe air supply port 158 formed in the head unit 136 even the vacuumsuction to form the envelope 2 with the gussets 61 begins.Consequentially, the envelope 2 would not be trapped in thedepressurized condition. In this way, the individual packages 3constituting the assembly 15 would not be compressed by depressurizedenvelope and thereby deformed. In addition, the finished package 14would not be undesirably deformed and therefore it is facilitated tostack a plurality of the finished packages 14 for bale packaging ordisplaying. The air inlet 159 extending to the air supply port 158functioning in the manner as has been described above may be provided inthe rear end wall 151 b of the main plate 151 or between the mainfrontal end wall 151 a and the main rear end wall 151 b or behind themain rear end wall 151 b. The air inlet 159 may be connected to apressurized air supply source such as a compressor so that the air inlet159 may be used to supply the envelope 2 b with pressurized air. In thepusher 101, timing control for starting and ending of air suctionthrough the air suction port 157 and for starting and ending of airsupply through the air supply port 158 can be done by providing thepackaging equipment with control mechanisms (not shown) operativelyassociated with these timing control operations. In the pusher 101, theV-shaped grooves 156 in the illustrated embodiment may be replaced byU-shaped grooves or the other various types of grooves.

In the pusher 101 according to the present invention, it is possible toprovide the upper sub-plate 152 or the lower sub-plate 153 also with theair supply ports functioning for the envelope 2 b in order to preventthe envelope 2 b from being trapped in the depressurized condition whenthese sub-plates 152, 153 move away from the envelope 2 b. It is notessential to provide the main plate 151 with such air supply ports as inthe illustrated embodiment but it is possible without departing from thescope of the invention to provide any one of the main plate 151, theupper sub-plate 152 and the lower sub-plate 153 depending on respectivesizes of the envelope 2 b, the assembly 15 and the head unit 136.

The head unit 136 of the pusher 101 according to the present inventionpreferably comprises three components, i.e., three plates 151, 152 and153 in the height direction T. However, it is possible without departingfrom the scope of the invention to replace the upper sub-plate 152 andthe lower sub-plate 153 provided as the separate components in theillustrated embodiment by these sub-plates 152, 153 integrally connectedto each other behind the head unit 136 so that these two sub-plates 152,153 may move together forward or backward. It is also possible withoutdeparting from the scope of the invention to save one of the uppersub-plate 152 and the lower sub-plate 153. In other words, the head unit136 comprising three components may be replaced by the head unit 136comprising two components in the height direction.

FIG. 11 is a diagram similar to FIG. 1 OA exemplarily illustrating amanner in which the pusher 101 is used. Referring to FIG. 11, the openend 5 of the envelope 2 b has been put on the bucket 21 b and the closedend 4 has moved into the bucket 21 b from the left hand and in themachine direction A. The closed end 4 has its inner surface exposed andfaces the assembly 15 a. The assembly 15 a comes in contact with theinner surface of the closed end 4 of the envelope 2 b as the assembly 15a is pushed by the pusher 101 into the bucket 21 b. The assembly 15 a ismoved into the envelope 2 b until the position shown by FIG. 10B isreached as the pusher 101 is moved forward. To bring the envelope 2 binto the state of FIG. 11, after the open end 5 has been put on thebucket 21 b, pressurize air may be injected from outside of the closedend 4 into the envelope 2 b and thereby the closed end 4 may be forcedto move into the bucket 21 b from the left hand as viewed in FIG. 11.

Referring to FIG. 11, the pusher 101 may be used to push the assembly 15a into the envelope 2 b to obtain a compactly finished package 14without trapping air inside the envelope 2 b in front of the assembly 15a.

FIG. 12 is a partial sectional view similar to FIG. 9, showing onepreferred embodiment of the head unit 136 in the pusher 101 according tothe present invention and FIG. 13 is a perspective view of the finishedpackage 14 obtained by using the head unit 136 shown by FIG. 12. Thehead unit 136 shown by FIG. 12 comprises the main plate 151 as the firstplate and the upper sub-plate 152 as the second plate. In this head unit136 also, the grooves 156 of the main plate 151 may be used to form theenvelope 2 b with the gussets 61 after the upper sub-plate 152 has movedaway from the envelope 2 b. The envelope 2 b indicated by imaginarylines in FIG. 12 is the envelope in a phase that the upper sub-plate 152is moving into the envelope 2 b and the envelope 2 b′ indicated also bythe imaginary line is the envelope in a phase that the gussets 61 aregradually formed as the upper sub-plate 152 moves away from the envelope2 b′. In the finished package 14 obtained by using this head unit 136,the heat-seal 2 e formed on the end wall 62 of the envelope 2 is not atthe middle as viewed in the vertical direction of FIG. 13 but biaseddownward. Such end wall 62 may be advantageously utilized when it isdesired to provide this end wall 62 with print of large graphic or logofor which it is undesirable to divide such graphic or logo in two.

While the pusher 101 and packaging equipment 110 including this pusher101 having been exemplarily described hereinabove with reference toFIGS. 6 through 13 are also suitable for packaging of the flexible andeasily deformable articles such as menstruation napkins and disposablediapers, it is obvious that these pusher 101 and packaging equipment 110can be effectively used for the other articles which are not easilydeformable.

1. A pusher used in packaging equipment, said pusher operating to pusharticles to be packaged into an envelope having a closed end and an openend opposite to said closed end, then to seal said open end concurrentlywith formation of gussets on both sides of said open end and thereby toobtain a finished package comprising said envelope and said articles tobe packaged, said pusher being characterized in that: said pusher isadapted for to-and-fro movement in a forward direction in which saidarticles to be packaged are pushed into said envelope and in an rearwarddirection opposed to said forward direction and includes a head unithaving a frontal end wall adapted to be pressed against said articles tobe packaged and to move into said envelope, a rear end wall opposed tosaid frontal end wall and both lateral walls defined between saidfrontal end wall and said rear end wall and extending in parallel toeach other in said forward direction; and said frontal end wall isprovided with an air supply port adapted to maintain afluid-communication between inside and outside of said envelope by anintermediary of said pusher so long as said frontal end wall lies insidesaid envelope; and said lateral walls are respectively provided with airsuction ports allowing said open end of said envelope to be formed withsaid gussets as said frontal end wall moves away from said inside ofsaid envelope in said opposite direction.
 2. The pusher defined by claim1 wherein said air supply port provided in said frontal end wall of saidhead unit is kept in fluid-communication with ambient air between saidfrontal end wall and said rear end wall, on said rear end wall or behindsaid rear end wall.
 3. The pusher defined by claim 1 wherein said airsupply port provided in said frontal end wall of said head unit isadapted to supply an inside of said envelope with pressurized air. 4.The pusher defined by claim 1 wherein said lateral walls arerespectively formed with V-shaped grooves extending from said frontalend wall toward said rear end wall and said V-shaped grooves are formedin respective surfaces thereof with said air suction ports.
 5. A pusherused in packaging equipment, said pusher operating to push a pluralityof articles to be packaged into an envelope having a closed end and anopen end opposite to said closed end, then to seal said open endconcurrently with formation of gussets on both sides of said open endand thereby to obtain a finished package comprising said envelope andsaid articles to be packaged, said pusher being characterized in that:said pusher is adapted for to-and-fro movement in a forward direction inwhich said articles to be packaged are pushed into said envelope and ina rearward direction opposed to said forward direction and includes ahead unit having a frontal end wall adapted to be pressed against saidarticles to be packaged and to move into said envelope, a widthdirection extending orthogonally to said direction of said to-and-fromovement and a thickness direction extending orthogonally to both saiddirection of said to-and-fro movement and said width direction; saidhead unit is divided in two, i.e., a first plate and a second plate faceeach other in said thickness direction or divided in three, i.e., afirst plate, a second plate and a third plate, said first plate beinginterposed between said second plate and said third plate wherein bothsides of said first plate in said width direction are respectivelyformed with V-shaped grooves extending in said direction of saidto-and-fro movement and utilized to form said gussets and said groovesare formed with ports connected to a vacuum suction source; said headunit operates in a manner such that, in a course of movement in saidforward direction of said pusher, said second plate and said third platecooperate with said first plate to push said articles to be packagedinto said envelope and, in a course of movement in said rearwarddirection of said pusher occurring after said articles to be packagedhave been fully pushed into said envelope, said second plate and saidthird plate move away from said envelope leaving said first platetherein, and thereafter said first plate moves away from said envelopeto subject said envelope to vacuum from said vacuum suction source; anda frontal end sub-wall defined by any one of said first, second andthird plates has an air supply port adapted to maintainfluid-communication between inside and outside of said envelope as longas said frontal end wall lies inside said envelope.
 6. The pusherdefined by claim 5 wherein said second plate and said third plate areintegrated with each other behind said head unit.
 7. The pusher definedby claim 5 wherein said air supply ports are adapted to supply an insideof said envelope with pressurized air.